finally a release date:
October 4.
It has some steep competition that week though:

Warner Bros. has now dated the George Clooney/Sandra Bullock sci-fi thriller for October 4. It’ll open against Robert Rodriguez’s Sin City: A Dame to Kill For, Star Wars Episode III: Revenge of the Sith 3D, Harrison Ford and Liam Hemsworth in Paranoia and Vince Vaughn’s latest, The Delivery Man.

In Gravity, Bullock and Clooney play two astronauts stranded in space when their ship is destroyed. It’ll also be released in IMAX.

a scifi movie in space that is not laser beams and action ship explosion scenes. This is a lot closer to Moon, Apollo 13, or Solaris being a thinking man's psychological-sci-fi film rather than a action-sci-fi genre film. Interesting release date choice with SWEP.3ROTS3-D that weekend. I'm sure in Gravity the spaceship's destruction scene will be pretty cool but based in science.

I'm guessing the sequence in "Mission to Mars" (2000) where the ship takes on micrometeorites and they have to abandon the ship will be something similar on an action level to this film.